The invention relates to a method for operating a Steckel mill having at least one reversing unit for rolling a rolled product and winding furnaces for the rolled product arranged on the entry side and the exit side with respect to the reversing unit. The invention also relates to an open-loop and/or closed-loop control device for carrying out the method, a Steckel mill with an open-loop and/or closed-loop control device of this type, a machine-readable program code and a storage medium.
In a Steckel mill, a rolled product, in particular a strip, is fed out from an entry-side winding furnace and is fed by an entry-side driver into a reversing unit for the initial pass. Following the first rolling pass, the rolled product is fed into an exit-side winding furnace. During this type of reversing process which is repeated multiple times, a head end and a foot end of the strip become more severely cooled than the central region of the strip. The stronger cooling results therefrom that, during the reversing process, in alternating manner, these strip regions are not kept at a high temperature in the winding furnace.
Due to the cold head end and the cold foot end of the rolled product or strip, the rolling force greatly increases there during the rolling pass relative to the central region of the strip. The reversing unit must therefore be designed for the high rolling forces that arise here. Due to the extreme rolling force spikes at the head and foot end of the rolled product, changes of thickness and/or flatness over the strip length can occur. As a result, the rolled product has a reduced quality. When a fault arises, caused by excessive cooling of the rolled product, the whole material is usually coiled up as scrap.
According to DE 19514475, this problem is counteracted in that heating devices are provided between the reversing unit and the winding furnaces, so that, above all, the part of the rolled product situated outside the heated winding furnaces can be brought to a temperature that is suitably adjusted to the remaining rolled product. However, this solution is characterized by a very high energy usage, whilst sufficient space is also required for the heating devices.